P38 rear light clusters

My 2001 P38 4.0 V8 HSE keeps insisting that either the indicator bulb or the brake light bulb has failed in one or other of the rear light clusters. The bulbs are fine and if I pull off the connector and clean it all up, it usually works again. For an hour or two, or even a day or two. Anyone got a solution to my little problem, please?

Have you tried new bulbs I know there OK but its got to be your next option

biketeacherdave said:

Have you tried new bulbs I know there OK but its got to be your next option

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Thanks for that. I did wonder about a 'make and break' on the bulbs - but on four of them? Been given a couple of new light clusters and a suggestion that I buy new connection blocks, so I suppose that's the next thing to try. If you can still find the right blocks.

I had a few bulbs out messages on the dash checked the bulbs all good just like you had me going back and checking more than once in the end I fitted new bulbs problem solved, over time even a bulb can go slightly high resistance and still function fine have you ever noticed when changing a single bulb it can look brighter than the other matching bulb ie off side/near side comparison.

It only takes a small difference in resistance to set off the dash warnings it seems, we all know how sensitive these cars are. How old are the bulbs ??? If you suspect the cluster connection block then use a contact cleaner in the block, check the terminals cluster end are they clean ? Or oxidised ?.

Thanks, Dave. Thought I might change the light clusters while waiting in Tesco's car park for my wife to do her shopping but they must be from an older car that had orange lenses, so my orange bulbs don't fit. Back to the drawing board! However, I will first try your advice of some new bulbs. I suspect the current ones are 2001 so it's well worth renewing them anyway.

Well the new bulbs seem to be working the miracle, although after only a few days I'm still keeping my fingers crossed. Thanks for the advice. Have a good Christmas.

Old Seadog said:

Well the new bulbs seem to be working the miracle, although after only a few days I'm still keeping my fingers crossed. Thanks for the advice. Have a good Christmas.

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That's good news

biketeacherdave said:

That's good news

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Still good news, so dare we hope the problem is sorted?

Who knew old bulbs "wore out?" I did... *smug face*

Thing is, when the current passes through the coil, it creates a tremendous resistance hence it heats up and glows.

However, resistance = heat and these coils expand and become soft, so when you are banging over pot holes and such, they are flexing and drooping slightly. This can make each individual coil touch and weld together, which given time will alter the resistance and cause errors in the can bus system as they draw more current to light up...

So, in essence, bulbs "can" wear out

Cheap & easy fix though

Good call Dave and happy new year OSD

A few weeks ago I kept getting the message that the left hand brake bulb had failed when it had not. Before I got the time to change the bulb the battery packed in. New battery, no more error message. Same bulb.

I had changed the battery without any effect on the error signals. Then, following Dave's advice, I replaced the four offending bulbs. Been going serenely on our way ever since, so thanks, Chaps. Brilliant. Now I have to replace the roof lining! Happy days.